To improve our understanding of the underlying mechanisms responsible for age-related ani gender-related differences in the performance of cognitive and psychomotor tasks, biological factors known to alter neural function will be measured and correlated with performance. Psychomotor tests known to be affect by age and gender will be administered to 100 healthy men and women ranging in age from 40 to 70+ years. The neurobehavioral battery will include measures of verbal memory and learning, motor speed and sensory-motor performance besides mood and personality profile. In addition, questionnaires for demographic information, medical history, hobbies and life long training history and a neurological examination will be assessed. We hypothesize that early, asymptomatic cerebrovascular disease as indicated by the presence of risk factors are biological markers of altered cerebrovascular function modulates neuropsychological performance. Risk factors for cerebrovascular disease, namely height/weight, blood pressure, heart disease (EKG), diabetes mellitus (fasting blood glucose) hyperlipidemia (e.g., cholesterol, LDL, HDL2, HDL3), alcohol and cigarette use will be measured. Cerebrovascular function will be quantitated with carotid flow studies using a Doppler Volume Flow Meter. The quantity and composition of atherosclerotic plaque in the carotid arteries will be quantitated with duplex scanning. White matter changes in the central nervous system believed to be secondary to cerebrovascular disease in normal aging will be visualized by using magnetic resonance imaging (MRI) of the brain. Electrophysiologic correlates of cerebral atherosclerosis will be determined with quantitative electroencephalography using power spectral analysis to be correlated with the other cerebrovascular measures and neurobehavioral performance. A second hypothesis is that age-related gender differences in motor speed (simple reaction time and finger tapping) are due in part to differences in physical activity. In the past physical activity has usually been obtained by self-report. We propose to accurately measure maximal aerobic capacity (VO2 max) and correlate the results with measures of motor speed. The third hypothesis is that alterations in peripheral sensory receptors (vibration, thermal perception thresholds) in the fingertips is an important mechanism responsible for age- related gender differences in sensory-motor performance (Purdue Pegboard). Using this approach we hope to determine the important mechanisms responsible for age-related and gender-related differences in verbal memory and learning, motor speed and sensory- motor-performance.